In the old days, cosmetic compositions were used mainly indoors. However, as leisure activities have been generalized recently and modern life styles have been changed correspondingly, cosmetic compositions have been frequently used outdoors. Particularly, in the old days, UV protecting cosmetic compositions were used mostly in summer seasons. However, as modern people enjoy outdoor activities and recognize hazard of UV rays more and more, there is a tendency for UV protecting cosmetic compositions to be used frequently throughout all the seasons besides summer seasons. Therefore, there is an increasing need for cosmetic compositions convenient to use and easy to carry.
Polyester-based urethane foam was developed accidentally by a German technical specialist in the late 1940's during which development of plastics was in the midst. Since such urethane foam is based on polyester, it is also called ester foam. Producing such urethane foam requires no advanced technology. Thus, polyester-based urethane foam has been produced generally and used in various industrial fields, particularly those requiring strong tensile force.
However, polyester-based urethane foam tends to be broken easily under a wet environment. In addition, it has a microcellular structure and low air permeability, and thus shows low cushiony feel, softness and flexibility. As a result, polyester-based urethane foam is not suitable for use in impregnating a cosmetic composition, particularly a liquid cosmetic composition. Under these circumstances, there is an imminent need for developing urethane foam suitable for use in impregnating a cosmetic composition.
Polyester-based urethane foam tends to be brittle under wet environment and has a small cell structure and low air permeability. Thus, polyester-based urethane foam shows low cushioning property, softness and flexibility, so that it is not suitable for impregnation with a cosmetic composition, particularly a liquid cosmetic composition. Therefore, there has been a need for developing urethane foam suitable for impregnation with a cosmetic composition.